title: Quantification of ethyl glucuronide in hair: effect of milling on extraction efficiency.
abstract: OBJECTIVE
  The objective of the study was to provide conclusive evidence for the effect of particle size reduction as by milling on the extractable content of ethyl glucuronide (EtG) of hair samples.
  
  
  METHODS
  A number of real case hair samples and two pooled hair materials with EtG contents in the range of 10-30 pg/mg were systematically compared with regard to the extraction yield of EtG after cutting to 2-3 mm length and pulverization with a ball mill. After the respective treatment the samples were submitted to aqueous extraction followed by quantification of EtG using HPLC-MS/MS.
  
  
  RESULTS
  It was unequivocally demonstrated that milling of hair samples prior to aqueous extraction significantly increases the extractable EtG content compared with cut hair. The effect ranged between 137 and 230% and was seen to occur regardless of the extent of pulverization. Cooling of samples was not necessary to prevent partial degradation of EtG during the grinding procedure.
  
  
  CONCLUSIONS
  The options currently employed at choice in analytical practice (cutting or milling) were seen to significantly affect the extractable amount of EtG in hair. This is suspected to influence the degree of equivalence of quantification results obtained in different laboratories as well as their respective classification of a test subject's drinking behaviour on the basis of currently recommended cut-off values.
authors.affiliation: Department of Analytical Chemistry, Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Mönch
authors.forename: Roland
authors.initials: R
authors.lastname: Becker
authors.forename: Irene
authors.initials: I
authors.lastname: Nehls
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards; D005965:Glucuronates / Q000032:analysis*; D006197:Hair / Q000737:chemistry*; D006801:Humans; D013048:Specimen Handling / Q000379:methods / Q000592:standards*; D015813:Substance Abuse Detection / Q000379:methods / Q000592:standards; D053719:Tandem Mass Spectrometry / Q000379:methods / Q000592:standards*
chemical_list: D005965:Glucuronates; C093924:ethyl glucuronide